Objectives: This study investigates a potential increase in mortality and in the demand for ambulance emergency services, in particular among the elderly, in Ticino during summer 2003. Methods: Mortality rates and emergency ambulance interventions rates were compared with the records from the previous years. We considered the whole population (mortality only), the population groups aged 65 and over, respectively 75 and over. Results: The mortality in the population was not significantly different from the previous years. The number of deaths among the elderly showed a small but significant deviation from the expected values during June 2003 first heat wave, with no significant impact on the seasonal results. The number of ambulance service interventions was larger than during the previous years. Conclusion:. These results are consistent with findings in other studies regarding Ticino. The heat waves (especially June), were correlated with a higher number of ambulance callouts. In addition to some geographic, climatic, and social factors that had a protective impact, the response of the emergency services is likely to have contributed to a certain reduction in mortality.